In certain cases, an injection performed using a syringe has the effect of generating longitudinal stress in the needle at the time of injection. There is a risk that this stress will cause the needle and/or its connecting adapter to separate from the syringe body during the injection. This is particular the case when it is necessary to inject a viscous product.
A screw connection known as a “luer-lock” connection partially solves this problem but is not in any way capable of preventing the needle from becoming unscrewed under said stress. Such unscrewing, even partial, may cause lesions in the surrounding tissue, as much as a result of the injection of the product as of the unwanted movement of the needle, particularly when this needle is curved or bent. This problem arises particularly in the field of ophthalmic surgery, in which viscous products and curved needles are used.